Ever witness a theist win an argument about the existence of god? Neither have I. That's why I'm an atheist. Self deception is easy for some people, though. This is how those who consistently lose arguments can pretend as though the reverse is true. I suspect they can't help it; but, for the benefit of mankind, let's not allow them the luxury. Anytime a theist exposes their natural hypocrisy (which is inevitable) in an argument, call them on it. For example...
1) Moving the goalposts. A typical strategy of the theist's brain is to pull one of these on itself (and anyone around who is unwary enough not to catch it). In response to a valid argument against some theist claim, citing observable evidence and scientific research, the theist will often say something to the effect of, "Oh, yes, but we don't know everything; there is so much mystery to the universe..." Stop. Rewind. Who was making a claim? The one who is now arguing against the possibility of being certain of claims since "we don't know everything." A good reply would be, "True; we don't know everything. But we do know that the claim you made five seconds ago is not true, based on the knowledge, x, which I just passed on to you. What your brain is trying to do is called 'moving the goalposts'; it is dishonest, and in this case, hypocritical. Beware: you are trying to deceive yourself. Now, back to x..."
2) Red herring. Another strategy of the "faith-head" is to change the subject in a way that makes his opponent look bad. The case I have in mind is the old standby, "People can believe whatever they want!" It comes in various alternative forms, like, "Why are you atheists always trying to force your beliefs on others?" or, "Live and let live, guys!" This always leaves the honest participant in the argument going, "Wha--?" It's funny to me how this is what is used in place of a real argument. In the murky world of emotions that the weak mind inhabits, it's a real winner: it allows you to dodge your opponent's valid points while simultaneously making him or her out to be an asshole. Usually this ends the argument, with all the namby-pamby folks patting themselves on the back for vanquishing the "troll." But it doesn't have to be this way: the true winner of the argument (the one who masters his emotions enough to remain honest) could stand his ground and say, "No. That's a different subject. We were talking about x, not about whether people can believe what they want to believe, or whether we should all get along. I agree with these platitudes, but they aren't the subject at hand. Your dodging my argument in this manner is called a 'red herring'; it is dishonest, and in this case, hypocritical. Beware: you are trying to deceive yourselves. Now, back to x..."
From these two examples (and there are many more) of hypocrisy among the incorrect, it would be easy to assume that theists don't care about truth; that they just want to be left alone to cherish their erroneous beliefs. But if this is true, then what is it that keeps them coming back for more? Could it be the truth-shaped hole in their heads?